re PR c++/50034 (Overload selection failure within class template)

	PR c++/50034
	* call.c (convert_arg_to_ellipsis): force_rvalue only in
	potentially evaluated context.

From-SVN: r177722

gcc/cp/ChangeLog

+2011-08-12  Jason Merrill  <jason@redhat.com>
+
+	PR c++/50034
+	* call.c (convert_arg_to_ellipsis): force_rvalue only in
+	potentially evaluated context.
+
 2011-08-12  Richard Guenther  <rguenther@suse.de>
 
 	* call.c (build_over_call): Instead of memcpy use an

gcc/cp/call.c

@@ -6097,7 +6097,7 @@ convert_arg_to_ellipsis (tree arg)
     {
       /* Build up a real lvalue-to-rvalue conversion in case the
 	 copy constructor is trivial but not callable.  */
-      if (CLASS_TYPE_P (arg_type))
+      if (!cp_unevaluated_operand && CLASS_TYPE_P (arg_type))
 	force_rvalue (arg, tf_warning_or_error);
 
       /* [expr.call] 5.2.2/7:

gcc/testsuite/ChangeLog

+2011-08-12  Jason Merrill  <jason@redhat.com>
+
+	PR c++/50034
+	* g++.dg/cpp0x/defaulted28.C: Add unevaluated case.
+
 2011-08-12  Uros Bizjak  <ubizjak@gmail.com>
 
 	* gcc.dg/builtins-67.c: New test.

gcc/testsuite/g++.dg/cpp0x/defaulted28.C

 // PR c++/49102
+// PR c++/50034
 // { dg-options -std=c++0x }
 
 struct A {
@@ -8,8 +9,9 @@ private:
   A(A const&) = default;	// { dg-error "private" }
 };
 
-void f(...) { }
+int f(...) { }
 int main() {
   A a;
   f(a); 			// { dg-error "this context" }
+  sizeof(f(a));			// OK because unevaluated
 }